A typical color silver halide photographic material contains at least one layer sensitized to each of the three primary regions of the visible spectrum. They usually contain at least one blue-sensitive layer with a yellow image dye forming coupler, at least one green-sensitive layer with a magenta image dye forming coupler, and at least one red-sensitive layer with a cyan image dye forming coupler.
In addition to the spectral sensitizing dyes used to sensitize the light-sensitive silver halide emulsion grains to the different regions of the spectrum and the yellow, magenta, and cyan dyes that are formed from dye-forming couplers to form the final color image, it is common to incorporate additional dyes or colorants for different purposes in the various light-sensitive and non-light sensitive layers. For example, absorber dyes (such as acutance dyes) are frequently employed in the light-sensitive layers to absorb light between the silver halide emulsion grains to reduce light scatter and improve image acutance or to control the light sensitivity (photographic speed). These dyes are described in numerous publications such as U.S. Pat. Nos. 4,312,941, 4,391,884, 4,956,269, and 5,308,747. It is also common to use filter dyes to regulate the spectral composition of the incident light falling on a particular light-sensitive photographic layer. These dyes may be used in a non-light-sensitive layer, which is arranged above a light-sensitive silver halide emulsion layer or between two light-sensitive emulsion layers in order to protect the underlying emulsion layers from the action of light of the wavelength absorbed by the dye. For example, many color photographic materials contain a yellow dye filter layer that is usually arranged between the blue-sensitive layers and the underlying green-sensitive layers and red-sensitive layers in order to keep blue light away from the green-sensitive layers and red-sensitive layers. Filter dyes are also described in many publications such as U.S. Pat. Nos. 5,213,956 and 5,776,667, GB published applications 695,873 and 760,739, and EP Publication 430,186A1. It is also known to use dyes as anti-halation dyes in a layer below the light-sensitive layers to prevent light from reflecting back into the emulsion layers from the backside of the film support resulting in unwanted light scatter and halation effects as described in U.S. Pat. Nos. 4,288,534, 4,294,916, 5,262,289, and 5,380,635. In general, all of these dyes, except for the color image dyes, are irreversibly discolored or almost completely washed out of the layers during photographic processing so that no unwanted coloration remains on the exposed and developed photographic film.
The use of pre-formed, permanent dyes in color photographic elements that are not discolored or removed during processing have also been disclosed. These dyes are used in color negative photographic materials to adjust the blue, green, or red densities to a standard level for a nominally exposed and processed color negative film in order to achieve optimum performance during printing onto photographic paper. Technological advances in color negative films have reduced the contribution of other film components to the overall blue, green, and red minimum densities (Dmin) and midtones. For example, features such as DIR technology have diminished the once dominant role that colored masking couplers played in defining color saturation. Similarly, advances in silver halide spectral sensitization have led to a lower level of retained sensitizing dyes. In order to operate effectively in these legacy systems, minimum and midtone densities have been adjusted in modern color negative films by the use of colored, but otherwise inert, materials. These dyes are also used in color transparency materials to provide a neutral appearance in the minimum density areas. It is well known to use permanent dyes for these purposes that are synthesized by the reaction of photographic couplers with oxidized color developing agents. The pre-formed dyes are typically dispersed in an organic solvent using conventional dispersion making techniques and are subsequently incorporated into one or more layers of the photographic element. These dyes often have the advantage of having the same chemical structure and dye hue as the color image dyes that are formed in the film in-situ during photographic processing. However, they are relatively insoluble materials that require high levels of organic solvents to provide stable dispersions. This necessitates use of increased levels of binder in order to retain good film physical properties. They also suffer from the disadvantages of being relatively inefficient light absorbers and rather expensive to synthesize compared to a number of commercially available dyes and pigments that are commonly used as colorants in other industries.
The use of yellow pigments as colorants for toner particles in color electrophotography is well known in the prior art as disclosed for example in U.S. Pat. Nos. 2,644,814 (Ernst), 3,345,293 (Bartoszewicz et al.), 3,998,747 (Yamakami et al.), and 4,035,310 (Mammino et al.). Colorants are also widely used in inkjet ink formulations as described in U.S. Pat. Nos. 5,977,207 (Yui et al.), 5,989,701 (Goetzen et al.), and 6,231,655 (Marritt). Yellow pigments have also been employed as colorants in a light sensitive materials containing silver halide, a polymerizable layer, and a reducing agent used for forming color proofs in the field of digital color printing as disclosed for example in U.S. Pat. Nos. 5,304,454, 5,326,667, 5,328,800, 5,612,167, and 5,714,303 (all by Yokoya et al.).
Color photographic materials have been designed with compounds that provide minimum density upon reaction with a color photographic developer. For example, in the Comparative Examples described below, one such color producing-compound is labeled as “CD-1”.